Collapsible core for centrifugal pipe molds



Nov. 1, 1949 J. J. NOLAN, JR

conmrsmw CORE FOR CENTRIFUGAL PIPE uows Filed Oct. 10, 1946 5 Sheets-Sheet 1 INVENTOR. Jb/m/ .I/Voz xm/ Jk ATTORNEY ATTORNEY J. J. NOLAN, JR 2,486,870

COLLAPSIBLE coma FOR CENTRIFUGAL PIPE MOLDS Filed Oct. 10, 1945 5 Sheets-Sheet 2 Nov. 1 1949 J. J. NOLAN, JR

' COLLAPSIBLE CORE FOR CENTRIFUGAL PIPE HOLDS Filed Oct. 10, 1946 5 Sheets-Sheet 3 INVENTQR Jay/v J/vm JR ATT RNEY Patented Nov. 1, 1949 COLLAPSIBLE CORE FOR CENTRIFUGAL PIPE MOLDS John J. Nolan, Jr., New York, N. Y., assignor to The Central Foundry Company, New York, N. Y., a corporation of Maine Application October 10, 1946, Serial No. 702,470

9 Claims. 1

The invention relates to collapsible cores for centrifugal pipe molds, particularly to permanent cores of metal or other material susceptible of re-use.

In forming the bell ends of cast iron pipe and the like, it is necessary to employ either a destructible core such as a baked or dry sand core, or a permanent core made in a series of segments which can be collapsed or separately removed so as to clear the groove on the inside of the bell. In the case of the destructible core, it is necessary to make a new core for each casting. To avoid this, segmental metal cores have been devised. However, the devices of this type which have been known or used heretofore have been of rather complicated construction or difficult to manipulate, involving the use of pivoted segments, cams, etc., and these or other disadvantages of such devices have restricted their usefulness.

It is an object of my invention to provide an improved collapsible core of simplified construction which is easy to manipulate and which forms a unitary assembly without the use of pivots or cams. Other objects and advantages of my invention will appear as the description proceeds.

In the drawings:

Fig. 1 is a central vertical longitudinal sectional view of a preferred embodiment of the invention, illustrating its application to a metal pipe mold for forming the inner surface of a bell end. The core segments are shown in their expanded, or casting, position.

Figs. 2 and 3 are transverse sectional views taken as indicated at 2-2 and 33, respectively, in Fig. 1.

Fig. 4 is a detail sectional view similar to a portion of Fig. 1, but showing the core segments in retracted, or collapsed position for removal of the core at the conclusion of a casting operation.

Fig. 5 is a transverse sectional view similar to Fig. 2, but showing the core segments in the collapsed position, corresponding in this respect to Fig. 4.

Figs. 6 and 7 are detail face views of larger and smaller core segments, respectively.

Fig. 8 is a detail sectional view taken on the line 8-8 of Fig, 1, showing one of the guiding arrangements between the radially movable segments and the retaining ring.

The invention consists, in its general arrangement, of a collapsible core comprising a series of core segments Ill and II, the outer surfaces l2 and I3 of which form an inner'pipe surface, and a retaining ring I4 arranged for engagement with the core segments to hold them in loosely assembled relationship for limited movement in a radial direction. In the preferred arrangement illustrated, the collapsible core fits into the bell end of a metal pipe mold l5 mounted for rotation about its axis for centrifugal casting as by means of suitable metal tires supported on pairs of flanged rollers motor driven to rotate the mold. The means for producing rotation of the mold is not a part of the present invention and conventional mechanism known to the art may be employed for this purpose. However, for illustration I have shown one of the tires l6 and one pair of flanged rollers I! on which the mold is supported for rotation.

The end of mold I5 is suitably contoured to produce surfaces It which form the outer surface of the pipe bell. Annular shoulders I9 and near the inside end of the mold, with the connecting coniform surface 2|, serve to position retaining ring 14 and locking plate 22 for holding the collapsible core in casting position. The outer periphery of the retaining ring is tapered to fit the mold surface 2|. Locking plate 22 is held in place by suitable fastening means such as wedges 23 driven into slots in the mold as shown. During casting, rotation of the mold causes these wedges to hold tight under the action of centrifugal force.

Retaining ring l4 comprises two elements arranged to be secured together to lock the core segments Ill and H in loosely assembled relationship thereto. The outer element comprises an axially extending annular section 24 terminating in an inwardly directed radially extending flange 25 forming an annular groove 26. The inner element comprises a cylindrical annulus 21 fixed to the outer element, as by screws 28 or otherwise, to lock the core segments in assembled relationship.

Core segments l0 and H can be formed with projections on their outer surfaces l2 and 13 which together form an annular ridge or bead 29 for producing a groove on the inside of the pipe bell. The core segments together form an annular assembly having a generally cylindrical portion 30 with an outwardly directed radially extending flange 3|, 3| for engagement with the annular groove 26 of the retaining ring, and an axially extending flange 32 forming an annular groove 33 to receive the end of the cylindrical portion 21 of the retaining ring. The annular core assembly is divided into a number of separate core elements along engaging surfaces 34 (Fig. 3) disposed at an acute angle to a plane containing the axis of the pipe surface or mold. These engaging surfaces 34 of the series of core segments are further arranged so that they form a re-entrant angle on two of the segments. In the series of four core segments illustrated, segments ID are formed with re-entrant angles as clearly shown in Fig. 6.

The width of the annular groove 33 in core segments II is greater than it is in core segments III, as shown in Figs. 6 and 7 at 33' and 33", respectively. Thus the radial movement of the several segments is limited to different extents. Specifically, the radial movement of the two segments IEI having the re-entrantanglesis limited to confine their movement to a shorter radial distance than the remaining segments H can move.

The core segments and retaining ring have complementary radially disposed surfaces .-for guiding the core segments. Thus, in the specific embodiment illustrated, the annular groove 26 has-guide means in the form of radially disposed ribs 35 for cooperation with grooves 33 in the .core segments to maintain their relative peripheral disposition during radial movement. .-I prefer to. employ additional guide means at the Also,

inner end of the core assembly, such as provided by the ribs 31' at the base of the annular groove 33, and cooperating grooves 38 in the ends of cylindrical ring element 21.

InFigs. 1, 2 and 3 the core segments are shown in their expanded, or casting position. During :casting they are held in-this position by the accomplishment of similar purposes.

It will be observed from Figs. 2 and 6 that the flanges 3| of core segments H] are highest at their central portion, tapering down at the ends. This allows for initial assembly of the segments withtheretaining ring. However, if desired,.the ring may be split into two semi-circular segments for assembly, in which case the flanges 3| may be of the same height throughout. The split ring is welded together after assembly of the core segments therewith. Inassembling the core illustrated in the drawings, the core segments .10 are hooked intothe groove 26 of retaining ring section 24 and separated to the maximum extent.

Then core segments II are inserted so as to engage the groove 25 of ring section 24. Next the cylindrical annulus 21 is .put in place and secured to ring section 24, completing the assembly.

A suitable charging trough is indicated at a in Fig. 1.

The-terms and expressions which I have :em-

ployed are used in a descriptive andnot a limiting sense, and Ihave no intention of excluding such equivalents of the invention described, orof portions thereof, as fall within the purview of the claims.

I claim: 1. A unitary collapsible core for a centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, and a retaining ring arranged for engagement with the core seg- .ments, the retaining ring and core segments having interlocked flanges and grooves with clearances between said projections and grooves or recesses to hold the core segments in loosely assembled relationship for limited movement in a true radial direction with relation to the mold.

2. A collapsible core for a centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, and. a retaining ring arranged for engagement with the coresegments, the retaining ring and core segments having interlocked flanges and grooves with clearances between said projections and grooves or recesses to hol'd'the core segments in loosely assembled relationship for limited movement in a true radial directionwith relation to the mold, the core segments andre-taining ring having complementary radially disposed surfaces for guiding the core segments.

3. A collapsible core for a centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, andia retaining ring arranged for engagement with'the core segments, the core segments and =retaining ring having complementaryradially extending-flanges and complementary axially extending flanges, said complementary radially and axially extending flanges being loosely interlocked to hold the segments in loosely assembled relationshipfor limited movement in.a radial direction.

4. A collapsible core for a centrifugal pipe mold comprising a series of core segments formingan inner pipe surface, and a retaining ring arranged for engagement with the core segments, the core segments and retainingrin-g having complementary radially extending flanges and complementary axially extending flanges to hold thesesments in loosely assembled relationship-for limited movement ina radial direction, the radially extending flange of the-retaining ring forming an annular groove for sliding engagement with the radially extending flanges of the core segments.

5. .A- collapsible core fora centrifugal pipe mold comprising a series of core segments forming an .inner pipe surface, and a. retaining. ring arranged for engagement Withthe core segments, the core segments and retaining ring having complementary radially extending flanges and complementary axially extending flanges to hold the segments in loosely assembled relationship for limited movement :in:a radial direction, the radially .extending flange of the retaining ring forming an annulargroove for sliding engagement with the radially extending flanges of the core segments, and the annular groove having radial guide means for cooperation with the core seg- ,ments ,tomaintain their relative peripheral disposition during said limited radial movement.

6. A collapsible core for-a centrifugal pipemold comprising a series of core segments forming an .innerpipe surface, and an annular retaining ring arranged for engagement with the core segments, the retaining ring-having anaxially extending an nular section terminating in an inwardly directed radially extending flange forming an annular groove, the core segments havingoutwardly directed radially extending flanges for engagement with said annular groove tohold the core segments in loosely assembled relationship for movement confined-substantially to a. radial direction.

7. A collapsible core fora centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, and-an annular retaining ring arranged. for engagement with the core segments,

the retaining ring having an axially extending annular section terminating in an inwardly directed radially extending flange forming an annular groove, the core segments having outwardly directed radially extending flanges for engagement with said annular groove to hold the core segments in loosely assembled relationship for movement confined substantially to a radial direction, and the retaining ring having a cylindrical portion fixed in a position to lock the core segments in said assembled relationship.

8. A collapsible core for a centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, and an annular retaining ring arranged for engagement with the core segments, the retaining ring having an axially extending annular section terminating in an inwardly directed radially extending flange forming an annular groove, the core segments having outward- 1y directed radially extending flanges for engagement with said annular groove to hold the core segments in loosely assembled relationship for movement confined substantially to a radial direction, and the retaining ring having a cylindrical portion fixed in a position to lock the core segments in said assembled relationship, the core segments having axially extending flanges forming in their assembled relationshi an annular groove to receive the end of the cylindrical portion of the retaining ring.

9. A collapsible core for a centrifugal pipe mold comprising a series of core segments forming an inner pipe surface, and an annular retaining ring arranged for engagement with the core segments, the retaining ring having an axially extending annular section terminating in an inwardly directed radially extending flange forming an annular groove, the core segments having outwardly directed radially extending flanges for engagement with said annular groove to hold the core segments in loosely assembled relationship for movement confined substantially to a radial di rection, and the retaining rin having a cylindrical portion fixed in a position to lock the core segments in said assembled relationship, the core segments having axiall extending flanges form ing in their assembled relationship an annular groove to receive the end of the cylindrical portion of the retaining ring, the width of the groove in at least one of the core segments being greater than the width of the groove in other core segments whereby the radial movement of the segments is limited to different extents.

JOHN J. NOLAN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,491,028 Byers Apr. 22, 1924 1,542,810 Anthony June 23, 1925 1,582,440 Uhrig Apr. 27, 1926 1,594,366 Hering Aug. 3, 1926 FOREIGN PATENTS Number Country Date 5,717 Great Britain 1888 

